Off Topic - aviation curiosity

I'm in Houston and I've noticed on and off over at least the last two
years what looks like a Cessna 182RG orbiting within sight of my house,
typically in the evenings. I'm guessing 3000 AGL, constant ~3 minute
turn rate over a fixed spot for several hours straight. It appears to
have a small teardrop shaped appendage on one side of the fuse between
the wing and the tail which stands off from the fuse a short distance.
It's made it's circles both clockwise and counter clockwise. Today I
first noticed it around 4pm and at 8pm I noticed it again although it
had moved the center of it's turn a few miles to the NE of where I first
spotted it. By 8pm, it's definitely dark out so visual observation of
something on the ground doesn't seem likely. I've always noticed it in
the late afternoons and into the early evening, but that doesn't mean it
hasn't been operating at other parts of the day.

I'm not a conspiracy theorist, but am curious if anyone might have any
thoughts as to what's going on.